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In polymers, such as plastics, thermal degradation refers to a type of polymer degradation where damaging chemical changes take place at elevated temperatures, without the simultaneous involvement of other compounds such as oxygen. [1] [2] Simply put, even in the absence of air, polymers will begin to degrade if heated high enough. It is ...
Molten polymers are non-Newtonian fluids with high viscosities, and the interaction between their thermal and mechanical degradation can be complex. At low temperatures, the polymer-melt is more viscous and more prone to mechanical degradation via shear stress. At higher temperatures, the viscosity is reduced, but thermal degradation is increased.
Thermal depolymerization (TDP) is the process of converting a polymer into a monomer or a mixture of monomers, [1] by predominantly thermal means. It may be catalyzed or un-catalyzed and is distinct from other forms of depolymerization which may rely on the use of chemicals or biological action.
In general, plastic will be affected by light, and it is best practice to keep plastic away from light sources as much as possible, especially during longterm storage. Thermal degradation affects the entire bulk volume of the polymer making up an object, and is strongly affected by the temperature and amount of light exposure. [14]
Aerobic degradation occurs gradually at room temperature, but almost all polymers are at risk of thermal-oxidation when they are processed at high temperatures. The molding or casting of plastics (e.g. injection molding) require them to be above their melting point or glass transition temperature (~200-300 °C). Under these conditions reactions ...
Included polymers are low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyamide 66 (PA66), styrene butadiene rubber (SBR), and high-density polyethylene (HDPE). The effects of degradation can also be characterized through scanning electron microscopy (SEM). For example, through SEM, defects like cracks and pits can be ...
If the residence time and/or melt temperature (temperature at melting) are too high, then thermal degradation or thermooxidative degradation will occur resulting in discoloration and reduced molecular weight, as well as the formation of acetaldehyde, and the formation "gel" or "fish-eye" formations through cross-linking.
Processes in the thermal degradation of organic matter at atmospheric pressure.. Thermal decomposition, or thermolysis, is a chemical decomposition of a substance caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes.